For power generation, stationary gas turbines are known, the rotors of which are assembled from abutting compressor disks and turbine disks. These rotor disks are clamped to each other by a central tie bolt and on their periphery carry rotor blades, which in the compressor are for compressing of ambient air, and which in the turbine are for conversion of electrical energy into mechanical energy by the expansion of a hot gas which is produced by the combustion of fuel with the compressed air. In order to protect the component parts of the turbine against the temperatures of the hot gas, these are actively cooled, for example by means of cooling air. For example, the rotor blades of the turbine are cooled by compressed air. Some of the air required for this is extracted from the compressor on the rotor side and guided into the inside of the rotor. The rotor disks have central holes by which the extracted air can flow through the rotor in the axial direction. Since the combustion chamber is located between the compressor and the turbine of the gas turbine on the casing side, the rotor in this axial section has a pipe which is coaxial to the longitudinal axis, for transmission of the extracted air, which pipe is supported between the oppositely disposed end faces of the last rotor disk of the compressor and the first rotor disk of the turbine. For this purpose, it is known that the two rotor disks have an annular slot located in the end face, in which engages the pipe for guiding of the cooling air. The cooling air separation pipe is provided with a special shrink fit so that it has an antirotation or antislip seat on the rotor disk, as the case may be.
Despite the shrink fit, operation-induced displacements or slips, as the case may be, of the cooling air separation pipe in relation to the rotor disk can happen, which occurs on account of the different thermally-induced expansion of the two component parts, especially during starting (cold start) and during shutting down of the gas turbine. These displacements can lead to a permanent plastic deformation of the pipe end in the comparatively thin-walled cooling air separation pipe. Different operating modes also lead to such wear so that leaks in the connection between the cooling air separation pipe and the rotor disk can occur. The leaks lead to losses and leakages in the cooling air flow, as a result of which the efficiency of the gas turbine reduces.
Furthermore, the manufacture of the shrink fit, by which the cooling air separation pipe bears under a pretensioning upon a supporting surface of the turbine disk, is costly, since the fabrication of the shrink fit requires a tolerance range of a few hundredths of a millimeter.